From mboxrd@z Thu Jan 1 00:00:00 1970 From: Charles Keepax Subject: Re: [RFC PATCH] ASoC: wm_adsp: Change ADSPs to be mixer widgets rather the PGAs Date: Wed, 18 Dec 2013 13:14:36 +0000 Message-ID: <20131218131436.GE11138@opensource.wolfsonmicro.com> References: <1387364024-15708-1-git-send-email-ckeepax@opensource.wolfsonmicro.com> <20131218112739.GH28455@sirena.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from opensource.wolfsonmicro.com (opensource.wolfsonmicro.com [80.75.67.52]) by alsa0.perex.cz (Postfix) with ESMTP id 8AC7626164C for ; Wed, 18 Dec 2013 14:14:37 +0100 (CET) Content-Disposition: inline In-Reply-To: <20131218112739.GH28455@sirena.org.uk> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: alsa-devel-bounces@alsa-project.org To: Mark Brown Cc: alsa-devel@alsa-project.org, patches@opensource.wolfsonmicro.com, lgirdwood@gmail.com List-Id: alsa-devel@alsa-project.org On Wed, Dec 18, 2013 at 11:27:39AM +0000, Mark Brown wrote: > On Wed, Dec 18, 2013 at 10:53:44AM +0000, Charles Keepax wrote: > > > Was also considering if it would be worth adding an > > additional snd_soc_dapm_dsp id? That could sit between > > mixers and pgas, but I can't really see any obvious issue > > with treating the DSP as a mixer and it is a much simpler > > change. Although I am open to writing the other change if it > > is preferred? > > One of the issues here was trying to ensure that the DSP started up with > its inputs stable so noise from them starting didn't propagage into the > algorithm and confuse it. The expecation with putting it as a PGA was > that it would start with the outputs mute and do a digital unmute to > bring them up. Since everything is digital this should all be more > robust than it would be for analogue. Muting the output is a little tricky though as a graph walk will be required to determine which output was connected, unless you have any handy ideas I have not spotted? I will start having a look to see what could be done on the muting front. Thanks, Charles